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authorShaohua Li <shli@fb.com>2016-02-26 03:24:42 +0300
committerShaohua Li <shli@fb.com>2016-02-26 20:44:56 +0300
commit6ab2a4b806ae21b6c3e47c5ff1285ec06d505325 (patch)
tree881693ece12cd8ce147f1a370370eb60928120b0 /drivers/md/raid5.h
parent27a353c026a879a1001e5eac4bda75b16262c44a (diff)
downloadlinux-6ab2a4b806ae21b6c3e47c5ff1285ec06d505325.tar.xz
RAID5: revert e9e4c377e2f563 to fix a livelock
Revert commit e9e4c377e2f563(md/raid5: per hash value and exclusive wait_for_stripe) The problem is raid5_get_active_stripe waits on conf->wait_for_stripe[hash]. Assume hash is 0. My test release stripes in this order: - release all stripes with hash 0 - raid5_get_active_stripe still sleeps since active_stripes > max_nr_stripes * 3 / 4 - release all stripes with hash other than 0. active_stripes becomes 0 - raid5_get_active_stripe still sleeps, since nobody wakes up wait_for_stripe[0] The system live locks. The problem is active_stripes isn't a per-hash count. Revert the patch makes the live lock go away. Cc: stable@vger.kernel.org (v4.2+) Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com> Cc: NeilBrown <neilb@suse.de> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5.h')
-rw-r--r--drivers/md/raid5.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index ae6068deefdf..517d4b68a1be 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -524,7 +524,7 @@ struct r5conf {
atomic_t empty_inactive_list_nr;
struct llist_head released_stripes;
wait_queue_head_t wait_for_quiescent;
- wait_queue_head_t wait_for_stripe[NR_STRIPE_HASH_LOCKS];
+ wait_queue_head_t wait_for_stripe;
wait_queue_head_t wait_for_overlap;
unsigned long cache_state;
#define R5_INACTIVE_BLOCKED 1 /* release of inactive stripes blocked,